This invention relates to a scoring die matrix such as for use in forming creases or score lines in cardboard carton blanks.
Cardboard or other card like material for forming, for example, carton blanks, is creased or scored to facilitate folding into its final shape by pressing it between a creasing rule of a cutting and creasing press and a creasing matrix strip. The matrix strip is a long flexible strip having a longitudinally extending channel formed therein which is slightly wider than the creasing rule and which is aligned with the creasing rule edge so that on closing the press, the rule edge urges the portion of the card to be creased into the matrix channel thereby providing a well defined crease. It will be appreciated that the matrix channel must be precisely aligned with the edge of the creasing rule.
One such matrix assembly is disclosed in my U.K. Patent No. 1474022. The disclosed matrix assembly comprises a flexible plastic strip having a channel formed along its longitudinal axis to cooperate with the creasing rule and a separate, flexible plastic locator strip. The locator strip has a slit formed along its longitudinal axis adapted to engage the creasing rule, and the matrix strip and locator strip are firmly removably bonded to one another with the slit aligned with the channel. An adhesive layer is provided on the base of the matrix strip. In use, the slit in the locator strip is fixed to the creasing rule of the cutting and creasing press and the latter is then advanced towards the press cutting plate in order to press the matrix assembly against the cutting plate where the adhesive layer on the base of the matrix strip then retains the strip on the cutting plate. The locator strip can then be separated from the matrix strip to leave the matrix strip on the cutting plate in alignment with the creasing rule.
The above system works well in practice but depends on two adhesive bonds, namely, a first bond between the locator strip and the matrix strip, and a second bond between the matrix strip and the cutting plate. The second of these bonds must be stronger than the first to enable the locator strip to be removed from the matrix strip when the latter is in place on the cutting plate without removing the matrix strip from the cutting plate.